KR100746745B1 - Method for transmitting broadcast message from master to slave of wireless communication - Google Patents

Abstract

Disclosed is a broadcast message transmission method comprising a plurality of broadcast packets between a master and a slave for transmitting and receiving data wirelessly. A method of sequentially transmitting a broadcast message consisting of a plurality of broadcast packets between a master and a slave that transmits and receives data wirelessly, the method comprising: a first step of transmitting a first packet in a broadcast message from a master to a slave; wherein the slave receives the first packet A second step of transmitting a predetermined non-receipt notification signal to the master if not received, a third step of retransmitting the first packet to the slave when the master receives the unreceived notification signal, and the master receiving the unreceived notification signal If not received, the first to third steps are repeated for the next packet of the broadcast message, and the fourth step is performed again from the first step until the transmission of the mode packet corresponding to the broadcast message is completed. . When transmitting a broadcast packet, by actively coping with the number of repetitive transmissions for the same packet according to the reception state of the slave, it is possible to ensure the reliability of the transmission and obtain the time efficiency allocated according to the broadcast packet of the master.

BLUETOOTH, BROADCAST, PACKET

Description

Method for transmitting broadcast message from master to slave of wireless communication

1 is a block diagram showing a broadcast message transmitted from a master;

2 is a block diagram showing that a broadcast packet in a broadcast message is multiplexed;

3 and 4 are diagrams illustrating a broadcast packet transmission process between a conventional master and a slave;

5 is a block diagram showing a broadcast packet divided according to a broadcast message and a slot in a wireless communication according to the present invention;

6 is a block diagram showing a channel formation state of Bluetooth devices;

7 is a block diagram illustrating in more detail the broadcast packet of FIG. 5;

8 is a block diagram illustrating the header of FIG. 7 in more detail;

9 is a diagram illustrating a broadcast packet transmission process between a master and a slave according to the present invention; and

10 is a flow diagram showing FIG.

Explanation of symbols on the main parts of the drawings

10: master 22, 24, 26, 28, 50: slave                 

60: access code 70: header

71: Active member address 72: Data type identification value

73: flow control value 74: response indication value

75: sequential number value 76: header error check value

80: Valid data area

The present invention relates to a message transmission method in wireless communication, and more particularly to a method for transmitting a broadcast message consisting of a plurality of broadcast packets between a master and a slave for transmitting and receiving data wirelessly.

Bluetooth is a communication technology that can transmit information such as voice data and video data at a maximum speed of 1 Mbps wirelessly at a distance of 10 to 100 m.

Bluetooth devices that communicate with each other by the Bluetooth communication method perform operations such as Inquiry, Inquiry Scan, and Page Sync for timing synchronization. Configure the connection status through which communication is possible. At this time, the Bluetooth device is set as a master and a slave according to its role to perform communication. The master established through this process can typically transmit and receive data with up to seven slaves. This state is called an active mode, and the slave at this time is called an active slave, and the communication structure thus formed is called a piconet. In addition, when communication is requested from seven Bluetooth devices, one or more active slaves are set to the communication standby state. This state is called a park mode and the slave is called a park slave.

크기 즉, 방송메시지(B_M)를 하나의 슬롯크기로 나누어져 패킷단위로 전송된다. 도 2는 방송패킷(B_P)을 전송하기 위해 마스터와 슬레이브간의 무선으로 연결된 채널상태에 따라 방송패킷(B_P)을 다중복사(multi-copy)하여 나타낸 블록도이다. 도 2에서는 각각의 방송패킷(B_P)을 K_BC번 다중 복사하여 도시하고 있다.1 is a block diagram illustrating a broadcast message. The broadcast message B _M consists of a plurality of packets B _P. Here, it consists of M packets. At this time, the broadcast message (B _M ) is one slot

That is, the broadcast message B _M is divided into one slot size and transmitted in packet units. 2 is a block diagram showing the broadcast packet _(P B) a multi-copy (multi-copy) in accordance with the channel state between the master and the slaves are connected wirelessly to transmit a broadcast packet (B _P). In FIG. 2, each broadcast packet B _P is duplicated by K _BC times.

In the Bluetooth system, the master repeatedly transmits the same broadcast packet K _BC times before sequentially transmitting the post-broadcast packet in order to increase the transmission reliability of transmitting the broadcast packet (B _P ) to the slave, and the repetition frequency (K _BC ) is the master. Can be determined according to the channel state in the initial communication between the slave and the slave. Therefore, the first broadcast packet (Pn = 1) of FIG. 1 is multiplied into K _BCs as shown in FIG. 2 and transmitted to the slave.

The master sets the Active Member Address (AM_ADDR) field in the header of the broadcast packet to "000" so that the slaves can identify that the packet is a broadcast packet. The slave can transmit data to the master only if the active member address field value of the packet transmitted from the master and the active member address value thereof are the same.

3 and 4 are graphs showing on the time axis of the broadcast packet transmission of the master and the broadcast packet reception of the slave.

로 설정되어 있다. 마스터는 이 시간동안 모든 슬레이브(S₁ 내지 S_N)로 동시에 동일한 방송패킷(Pn = 1)을 전송한다. 마스터로부터 전송된 방송패킷(1)을 수신한 슬레이브들은 액티브멤버주소 필드 값("000")이 자신의 액티브멤버주소와 다른 경우, 다음 슬롯

동안 마스터에게 어떠한 패킷도 전송 할 수 없다. 또한, 블루투스 시스템에서는 데이터 송수신에 대한 응답(ACK)을 정의하고 있지 않기 때문에 슬레이브들은 수신한 방송패킷에 대한 응답을 알려주지 못하며, 마스터는 슬레이브들이 방송패킷을 정상적으로 수신했는지의 여부를 알 수 없다. 따라서, 마스터는 모든 슬레이브들이 방송 패킷을 정상적으로 수신했는지의 여부를 알 수 없다. 그래서 마스터는 하나의 방송패킷을 슬레이브와 초기통신을 통해 설정된 반복횟수(K_BC) 만큼 반복 전송하게 된다. 즉, 마스터는 하나의 방송패킷에 대해 이전에 전송한 패킷에 대한 전송 성공 여부와 상관없이 무조건 K_BC번만큼 재 전송하게 된다. Referring to FIG. 3, a broadcast time during which a master transmits a unit broadcast packet B _P to a slave is

Is set to. The master simultaneously transmits the same broadcast packet (Pn = 1) to all slaves S ₁ to S _N during this time. Slaves that receive the broadcast packet 1 transmitted from the master, if the active member address field value ("000") is different from their active member address, the next slot

No packets can be sent to the master. In addition, since the Bluetooth system does not define an acknowledgment (ACK) for data transmission and reception, the slaves do not inform the response of the received broadcast packet, and the master cannot know whether the slaves normally receive the broadcast packet. Thus, the master cannot know whether all slaves have normally received the broadcast packet. Therefore, the master repeatedly transmits one broadcasting packet by the set repetition number (K _BC ) through initial communication with the slave. That is, the master retransmits K _BC unconditionally for one broadcast packet regardless of whether the packet has been successfully transmitted.

×2)}[

]시간동안 불필요한 시간 낭비를 하게 된다.Referring to a of FIG. 4, the channel state of the same broadcast packet transmitted repeatedly K _BC times in the Bluetooth system is good, and thus, the broadcast packet is normally received at a second time before all slaves are repeatedly transmitted K _BC times. In this repeated transmission up to the second, even if all the slaves have received the normal broadcast packet, since the master does not know the reception status of the slave, it continues to transmit repeatedly as the initial set number of repetitions (K _BC ). In this case, the master performs unnecessary repeated transmissions of (K _BC -2) times for the same packet. In addition, the master is temporally {(K _BC -2) × (

× 2)} [

] Waste unnecessary time for hours.

Referring to b of FIG. 4, if there is a slave S _{NR that} is not normally received because of noise on a channel among the same broadcast packets repeatedly transmitted K _BC times in the Bluetooth system, transmission reliability cannot be guaranteed. In addition, even if the state of the transmission channel changes during the transmission of the packet from the master, since the initially determined packet repetition number of transmissions (K _BC ) cannot be changed, there is a problem in that the channel state cannot be actively coped with.

An object of the present invention for solving the above problems is to ensure the reliability of the transmission by enabling the master to check whether the slave received the broadcast packet when transmitting the broadcast packet from the master to the slave over the air, The purpose is to increase the efficiency of broadcast packet allocation time.

The method for transmitting a broadcast message between a master and a slave according to the present invention for achieving the above object is a method for sequentially transmitting a broadcast message consisting of a plurality of broadcast packets between a master and a slave for transmitting and receiving data wirelessly, A first step of transmitting the first packet in the message from the master to the slave, a second step of transmitting a predetermined non-receipt notification signal to the master if the slave has not received the first packet, and a master receiving the non-receipt notification signal to the master A third step of retransmitting the first packet to the slave, and a first step to a third step for the next packet of the broadcast message if the master does not receive the unreceived notification signal, and a mode corresponding to the broadcast message Fourth step to perform again from the first step until the transmission of the packet is completed It includes.

Prior to the second step, the broadcast packet received sequentially after the first broadcast packet is received in the transmission slot section after receiving the first broadcast packet is identical to that of the first packet. Determine whether or not.

According to the present invention, when the master transmits a broadcast packet, it is possible to guarantee the reliability of the transmission by actively coping with the number of repetitive transmissions for the same packet according to the reception state of the slave, and obtain the time efficiency allocated according to the broadcast packet of the master. .

Hereinafter, with reference to the drawings will be described the present invention in more detail.                     

First, the present invention will be described in more detail with respect to broadcast packets.

FIG. 5 is a block diagram illustrating a broadcast packet (B _P ) divided according to a broadcast message (B _M ) and a slot in wireless communication. In wireless communication, such a broadcast message BM is transmitted to a slave in packet units, that is, in a broadcast packet B _P.

6 is a block diagram illustrating a channel formation state of Bluetooth devices. The master 10 performs an inquiry to transmit its driving frequency to the surrounding slaves on a channel (air). The slaves perform an inquiry scan that synchronizes with the received driving frequency of the master 10. Thereafter, the master 10 performs a page for transmitting its driving timing clock to the slaves. The slaves perform a page scan that synchronizes with the received driving timing clock of the master 10. In this way, the master 10 and the slaves 22, 24, 26, and 28 connected on the channel perform active mode communication. At this time, the master 10 and the slaves 22, 24, 26, 28 may perform one-to-one data transmission and reception synchronously, but may also transmit necessary data to the slave through a broadcast packet. On the other hand, the slave which does not need to transmit or receive data as compared to the active mode is called a park slave 50, and this state is called a park mode or a power saving mode. The park slave 50 in the power saving mode synchronizes with the master 10 through intermittent transmission of data from the master 10. The broadcast packet described in the present invention refers to data transmitted from the master 10 in communication between the master 10 and the slaves 22, 24, 26, and 28 in an active communication mode.

7 is a block diagram illustrating in more detail the broadcast packet according to the present invention. The broadcast packet B _P divided by the broadcast message B _M by the packet from the master is an access code 60 located at the top of the packet and a header next to the access code 60. And a valid data (PAYLOAD) 80 located after the header 70 and the header 70. Therefore, the access code (ACCESS CODE) 60 is arranged at the position (LSB: least signification bit) transmitted first in time, and the valid data (PAYLOAD) (80) at the position (MSB: most signification bit) transmitted last. ) Is placed.

The access code 60 is used for frequency synchronization and timing synchronization between the master and the slave. In addition, DC offset is used for compensation and data identification. The header 70 includes link information between a master and a slave and consists of six fields. The valid data (PAYLOAD) area 80 stores valid data sent from the master to the slave.

8 is a block diagram illustrating the header HEADER 70 of FIG. 7 in more detail. The header 70 includes an active member address (AM_ADDR) 71, a data type identification value (TYPE) 72, a flow control value (FLOW) 73, a response indication value (ARQN) 74, and a sequential number value ( SEQN) (75), header error check value (HEC) (76).                     

The Active Member Address (AM_ADDR) 71 is a bit value for identifying a broadcast packet for an address and transmission data for a slave connected to a master. Here, the bit value of the active member address 71 is preferably set to 3 bits. The data type identification value (TYPE) 72 is an identification bit value in which a broadcast packet transmitted from a master corresponds to synchronous (SCO: synchronous connection oriented) or asynchronous (AC) connectionless (ACL). Here, the bit value of the data type identification value (TYPE) 72 is set to 4 bits.

Flow control value (FLOW) 73 is a bit value for controlling the transmission node of the packet through asynchronous transmission. Here, the bit value of the flow control value FLOW 73 is set to 1 bit. The response indication value (ARQN) 74 is a bit value used to inform the successful transmission of valid data 80. Here, the bit value of the response instruction value (ARQN) 74 is set to 1 bit. The sequential number value (SEQN) 75 is a predetermined bit value set to vary according to retransmission or sequentially post-transmission for the packet transmitted from the master. In addition, the sequential number value (SEQN) 75 may be set to the numbered bit value for the broadcast packet transmitted from the master. Here, the bit value of the sequential number value (SEQN: Sequence Number) 75 is set to 1 bit. The header error check value (HEC) 76 is a bit value configured to perform a full error check on the header 70 of the received broadcast packet. Here, the bit value of the header error check value (HEC) 76 is set to 8 bits.

9 is a diagram illustrating a broadcast packet transmission process between a master and a slave according to the present invention.                     

The master transmits the first broadcast packet to the slave in the transmission slot section T1, and the slave receives the transmitted data. At this time, if the active member address value is "000" from the packet header of the received data, the slave recognizes that this packet is a broadcast packet and receives subsequent valid data. The slaves that receive the normal broadcast packet process the received first broadcast packet and wait for the next broadcast packet.

If no signal is received during the transmission slot section T1, the slave transmits a predetermined short packet SP to the master at the time when the waiting slot section R1, which is a section waiting for the master to start, is started. Here, the short packet is preferably set to a single bit of data having a signal level of a predetermined value or more to minimize the size of the data. The master receives a short packet (S _P) receives and transmits a first broadcast packet re-transmission in the next slot interval (T2). At this time, the slave that has already received the first broadcast packet in the first transmission slot section T1 determines whether it is the same number as the first broadcast packet received through the sequential number value 75 in the header portion of the first broadcast packet retransmitted from the master. If it finds a broadcast packet of the same number, it ignores and waits for the next broadcast packet.

This operation is repeated until all broadcast packets transmitted from the master are received by the slave.

10 is a flowchart illustrating a process for increasing broadcast message transmission efficiency in wireless communication according to the present invention. In the present invention, a broadcast message is sequentially transmitted in a packet unit (B _P ) between a master and a slave that transmits and receives data wirelessly. In this figure, a process of transmitting a first broadcast packet and a second broadcast packet to a plurality of broadcast packets is shown. This will be described.

In the present invention, as shown in FIG. 5, a first broadcast packet is first transmitted from a master packet to a slave among broadcast packets sequentially divided into packet units B _P in the broadcast message B _M (S100). At this time, the master sets the start value of the active member address of the broadcast packet header to "000" and the sequential number value (SEQN) according to the slave and the preset value. The master can set the sequence number (SEQN) arbitrarily according to the appointment with the slave. If the sequence number is set to 1 bit, if the bit value is "0", it indicates that it is the same broadcast packet as the previously transmitted broadcast packet. If the bit value is "1", it indicates that the broadcast packet is different from the previously transmitted broadcast packet and can be set in advance between the master and the slave. The slot that adds the time for transmitting a broadcast packet from the master to the slave and the time for receiving the broadcast packet from the slave is called a transmission slot section T1.

로 설정되어 있다.After the transmission slot section T1 is finished, the slave determines whether the broadcast packet transmitted from the master has been received (S200). If the slave does not receive the broadcast packet, the slave transmits a predetermined non-receipt notification signal to the master for a short time (S300). This unreceived notification signal is called a short packet. The unreceived notice signal may be such that the power level of the signal can be sufficiently received by the master. On the other hand, the master does not receive a broadcast packet for a time from the time when the transmission slot interval (T1) ends until the time of transmitting the broadcast packet again, and waits for the reception notification signal received from the slave. The reception standby period of such an unreceived notification signal is called a standby slot section R1. Here, it is preferable that the transmission slot section T1 and the standby slot section R1 are set to slots of the same size. Each slot spans 625

Is set to.

The master receives the short packet, which is a non-receipt notification signal transmitted from the slave (S400). At this time, the unreceived notification signal may be attenuated according to the channel characteristics during transmission. However, it is designed to have a sufficient signal level so that there is no problem in receiving from the master.

The master receiving the non-receipt notification signal retransmits the broadcast packet to the slave (S500). At this time, the broadcast packet repeats S200 to S500 until transmission to all slaves.

On the other hand, if it is determined in step S200 that the broadcast packet is received, the master transmits the next broadcast packet to the slave in the next transmission slot interval (T2) (S600). After the transmission slot section T2 is finished, the slave determines whether the next broadcast packet is received in the next waiting slot section R2 (S700). If it is determined that the broadcast packet is not received according to the determination of whether the slave receives the broadcast packet, the process returns to step S300. In addition, if it is determined that the broadcast packet is received by the slave according to whether the broadcast packet is received, the slave determines whether the same packet as the previously received broadcast packet through the sequential number value (SEQN) of the received broadcast packet header part. If the received broadcast packet is different from the previously received broadcast packet according to the sequential number value, it is determined whether the currently received broadcast packet is the last broadcast packet M of the broadcast message (S800). In step S800, if the last broadcast packet (M), the master terminates the broadcast packet transmission, and if not the last broadcast packet (M), and returns to step S600.

In the above detailed description, the broadcast packet transmission between the master and the slave by Bluetooth has been described, but the same may be applied to the wireless communication for all communication equipments capable of transmitting and receiving data wirelessly.

According to the present invention, when the master transmits a broadcast packet, by actively coping with the number of repetitive transmissions for the same packet according to the reception state of the slave, it is possible to ensure the reliability of the transmission and increase the time efficiency allocated according to the broadcast packet of the master. have. In the above, specific preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims. will be.

Claims (13)

In the method for sequentially transmitting a broadcast message consisting of a plurality of broadcast packets between the master and the slave for transmitting and receiving data wirelessly, Transmitting a first packet in the broadcast message from the master to the slave; A second step of transmitting a predetermined non-receipt notification signal to the master when the slave does not receive the packet; Retransmitting the packet to the slave when the master receives the non-receipt notification signal; And When the master does not receive the unreceived notification signal, the first to third steps are repeated for the next packet of the broadcast message, until the transmission of the mode packet corresponding to the broadcast message is completed. And a fourth step of performing the first step again from the first step. delete The method of claim 1, Each packet is transmitted within a predetermined transmission slot section, and a waiting slot section for receiving the unreceived notification signal is set between each transmission slot section, and the slave is sent to the master within the waiting slot section. And transmitting the non-receipt notification signal. The method of claim 3, wherein And the transmission slot section and the standby slot section are set to slots of the same size. The method of claim 4, wherein The non-receipt notification signal is a short packet transmitted for a short time compared to the broadcast packet is a method for transmitting a broadcast message between the master and the slave. The method of claim 5, And the short packet has a signal level greater than or equal to a predetermined level. The method of claim 6, And the short packet is a single bit of data. The method of claim 3, wherein And determining whether the newly received packet is the same packet as the previously received packet, based on predetermined portion data of the packet previously received by the slave. How to send a broadcast message between. The method of claim 8, The predetermined portion is one bit of data in the packet, the value of one bit is alternate as the packet transmitted by the master is changed, the method of transmitting a broadcast message between the master and the slave. The method of claim 8, The predetermined portion is a method for transmitting a broadcast message between a master and a slave, characterized in that the header having data on the characteristics of each packet. The method of claim 10, The header, An active member address which is a predetermined bit value for identification of a broadcast packet for the address and transmission data for the slave connected to the master; And And a sequential numbering value which is a predetermined bit value set to be retransmitted for the packet transmitted from the master or sequentially according to the next packet transmission. The method of claim 11, The header, A data type identification value, wherein said packet is an identification bit value corresponding to synchronous or asynchronous use; A flow control value which is a bit value for controlling a transmission node of the packet; And And a response indication value, which is a bit value for informing the master of the successful transmission of the broadcast packet received to the slave. The method of claim 12, The header further comprises a header error check value which is a bit value set to perform an error check on the received header.

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